+xWell, strike me with a kipper!, now I think about it, my habit is to stop looking at skydemon once the field is in sight, so it was a bit of a silly request in light of that (and presumably why I didn't pick up on the feature being pre-existant).
But now I know the feature is there and the circuit is not so busy as to afford me a look at my ipad then it will be usefull. [...]
You do need need to zoom in a bit to see it. If you use the new(ish) approach selection it automatically zooms you in enough to see it. In hindsight, I'm also not sure how it works with georeferenced plates.. Bear in mind that it doesn't have noise sensitive areas in it for ALL airports - only what appears to have been submitted - so a lack of red circles doesn't mean there aren't any NS areas!!